Chapter 0: Problem 16
Sketching a Graph by Point Plotting In Exercises \(7-16,\) sketch the graph of the equation by point plotting. \(y=\frac{1}{x+2}\)
Short Answer
Expert verified
The graph of the function \(y=\frac{1}{x+2}\) plots points around a vertical asymptote at \(x=-2\). To the left of this asymptote, the graph trends downwards, while to the right, it goes up.
Step by step solution
01
Understand the Equation
The given equation is \(y=\frac{1}{x+2}\). This is a rational function, which means it will have an undefined value where the denominator equals zero, which is \(x = -2\).
02
Choose Values for x
Choose some values for x to plot the points. It's helpful to include values on either side of the undefined point (-2). In this case, you might choose -3, -2.5, -1, 0, 1.
03
Solve for y
Substitute each x value into the equation to find the corresponding y value. For example, if x=-3, \(y = \frac{1}{-3 + 2} = -1\), if x=-2.5, \(y = \frac{1}{-2.5 + 2} = -2\) and so on. Do this for all chosen x values.
04
Plot Points and Draw the Curve
Plot each point on a graph and draw a smooth curve that fits the points. Keep an eye out for the undefined point at \(x=-2\) where the graph will have a vertical asymptote.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Vertical Asymptotes
When dealing with rational functions like \( y = \frac{1}{x+2} \), vertical asymptotes are key features on the graph. A vertical asymptote occurs when the denominator of the rational function becomes zero, making the function undefined at that x-value. In our equation, the denominator \( x + 2 \) becomes zero when \( x = -2 \). This is the location of the vertical asymptote.
Visualize the vertical asymptote as an imaginary vertical line at \( x = -2 \). The graph will approach this line but will never touch or cross it.
Keep in mind:
Visualize the vertical asymptote as an imaginary vertical line at \( x = -2 \). The graph will approach this line but will never touch or cross it.
Keep in mind:
- Vertical asymptotes indicate where the graph of the function may spike upward or downward to infinity.
- Always look for values of \( x \) where the denominator equals zero to find potential vertical asymptotes.
- This asymptotic behavior is crucial for sketching the graph accurately.
Plotting Points
Plotting points helps to visualize the graph of a rational function by marking specific coordinates. Begin by selecting several \( x \)-values to input into your function. It's smart to pick values around the vertical asymptote to understand how the graph behaves near these crucial points.
Let's use \( y = \frac{1}{x+2} \):
Let's use \( y = \frac{1}{x+2} \):
- Choose \( x = -3 \), you get \( y = -1 \).
- For \( x = -2.5 \), find \( y = -2 \).
- If \( x = 0 \), then \( y = \frac{1}{2} \).
- Suppose \( x = 1 \), lastly \( y = \frac{1}{3} \).
Rational Functions
A rational function is a fraction where both the numerator and denominator are polynomials. In our exercise, \( y = \frac{1}{x+2} \), the numerator is \( 1 \), a constant, and the denominator is \( x+2 \) a simple linear polynomial.
Important properties include:
Important properties include:
- Rational functions can exhibit holes (removable discontinuities) where both numerator and denominator are zero.
- They often have horizontal or slant asymptotes, in addition to vertical ones, affecting the behavior at infinity.
- Simplifying the rational expression is crucial when the numerator or denominator can be factored further.
Asymptotic Behavior
The term 'asymptotic behavior' describes how the graph of a function behaves as it goes towards an asymptote. This behavior is unmistakable in rational functions due to their denominator-driven characteristics.
Consider these types of asymptotic behaviors:
Consider these types of asymptotic behaviors:
- **Near Vertical Asymptotes**: As the value of \( x \) approaches the vertical asymptote (\( x = -2 \) for our function), the function \( y \) will tend toward positive or negative infinity. This means the graph will spike upwards or downwards steeply.
- **At Infinity**: For many rational functions, there are also horizontal asymptotes that show the value the function approaches as \( x \) goes to either positive or negative infinity. Our function's horizontal asymptote in this case is \( y = 0 \).
- **Graph Behavior**: Observing how the function stretches towards the asymptotes helps in accurately sketching the curve of the graph.